DYED-in-the-wool Brexiters have always told us not to worry about the potential issue of a hard border on the island of Ireland. There will be no border checks, they say; there is no risk of a return of the Troubles; technology will solve it, including, according to some of the more bizarre suggestions, drones and air balloons. But an awkward question has haunted the Brexiters – and indeed, all of the Brexit negotiations: how, exactly, is the hard border to be avoided?

This week, the European Research Group, which supports a hard Brexit, said it had the answers. Existing procedures could continue to be used to avoid the need for border checks, they said. Larger companies could also use trusted trader schemes to clear their goods for export and import, and extra customs declarations could be incorporated into the existing system of VAT returns. The European Research Group made it all sound so easy.

But how practical are their plans really? What is certainly welcome is the more realistic and sober tone from the ERG – they seem to have finally recognised that the border is an actual issue and asserting that it isn’t a problem is not enough. It is also true that other border situations – particularly the border between Sweden (which is a member of the EU) and Norway (which is not) – demonstrate how technology can make things easier.

However, the ERG has not been able to magic away the detailed problems and their potentially serious consequences. Yes, the Norway/Sweden border is much easier than it could be because of technology, including IT systems that allow goods to be declared to customs before they reach the border, but checks are still required and that can mean a wait at the border for drivers.

The issue in Northern Ireland is the potential effect such border checks could have on the peace and normality of communities on both sides. Again, the ERG and other Brexiters have been guilty of waving away the risk, but just listen to Northern Ireland’s top police officer George Hamilton: he said this week the notion that we do not need to worry about security and stability is wrong and that any physical infrastructure at the border could become a target for dissident republicans.

That kind of warning should not be lightly dismissed, particularly at a time when frustration is high over the suspension of the Stormont Assembly. It should also be remembered that even the Canada-style trade deal hard Brexiters seem to favour would involve border checks and a risk to the free-flow of business across the border.

No one appears to want a return to physical checks at the Northern Ireland border. But a way to avoid that without all of the United Kingdom remaining in the customs union has still to be found. The European Research Group appears to believe it has cracked the problem. It hasn’t.